A spatial light modulator (SLM) includes of an array of optical elements (or pixels) in which each element acts independently to modulate incident light. The incident light beam may be modulated in intensity, phase, polarization or direction. The majority of spatial light modulators are intensity modulators. In such devices, often the intensity modulation causes some phase modulation, but the phase modulation is not typically done independently of the intensity modulation.
An example of an intensity modulation type of SLM is a Grating Light Valve™ (GLV™) device from Silicon Light Machines Corporation of Sunnyvale, Calif. The GLV™ device switches and modulates light intensities via diffraction. The GLV™ device is comprised of many parallel highly-reflective micro-ribbons that are suspended over an air gap above a silicon substrate. When the ribbons of a GLV™ pixel are co-planar, incident light becomes specularly reflected (like a mirror) from the GLV™ pixel. By deflecting alternate ribbons of a GLV™ pixel, the incident light may be controllably diffracted from the GLV™ pixel.
It is highly desirable to improve spatial light modulators for use in a variety of applications.